1. Field of the Invention
This invention relates an arrangement for shifting gears on a marine winch, and more particularly, to an improved cam and shift-arm arrangement for the marine winch shown in U.S. Pat. No. 4,301,690.
2. Prior Art
U.S. Pat. No. 4,301,690 to Cavanagh discloses a marine winch gear shifting apparatus. This U.S. Pat. No. 4,301,690 is incorporated herein by reference in its entirety. The gear shifting means of the '690 Patent is a marine winch that utilizes a drive-shaft with a plurality of freely rotatable gears mounted thereon, and means for making a driving connection between the drive-shaft and any one of the gears. Through the operation of means actuated by limited reverse rotation of the drive-shaft, the connection of the drive-shaft is shifted to a second gear while the first gear is released. The shifting of the connection of the drive-shaft successively to all of the other gears is accomplished in the same manner, mainly, by stopping the drive-shaft and reversing its rotation through a limited angle which movement actuates means for connecting the next gear to the drive-shaft while releasing the previously connected gear. This procedure may be continuously repeated, shifting the connection with the drive-shaft progressively through all of the gears in a predetermined sequence and then returning the connection to the first gear.
As may be seen, however, in FIGS. 4-8 of the above identified '690 Patent, a rotatable cam designated by the numeral "66", has a cam surface 92 with a shoulder thereon which acts as an engager. A pocket, designated by the numeral "96" in the '690 Patent, is arranged to receive the follower, designated by the numeral "80" above the shift arm which is designated by the numeral "72". Proper timing and coordination between the shift-arm 72 and the rotation of cam 66 permits shifting between the gears. The prior art follower 80, which is a pin, may get caught in the cam pocket 96, and be sheared off, or locked therewithin. This may result in a nonfunctioning marine winch.
It is an object of the present invention, to provide an improved shifting mechanism over such as that shown in the prior '690 Patent.
It is a further object of the present invention, to provide a passive shifter arrangement useful in a marine winch as represented in the '690 Patent, which shifter arrangement permits the rotatable cam plate to rotate when necessary, either in a clockwise or counter-clockwise direction, without damaging the mechanism.
It is also a further object of the present invention, to provide a shifting mechanism for a marine winch of the type shown in the '690 Patent, which shifting mechanism is more economical, safer to use and easier than the shifting mechanisms shown in the prior art.